Olefin polymerization catalysts have many uses in industry. Hence, there is an interest in developing new catalyst systems that increase commercial usefulness and enable the production of polymers having improved properties.
Some supported catalyst systems, including metallocene catalysts, have been disclosed. For example, WO 96/00245 describes a method for forming silica supported catalyst systems. Davison 948 silica is used in Examples 1 and 2. WO 96/00243 describes methods for supporting metallocene catalyst systems for the polymerization of propylene. In the examples, Davison 948 silica is used as are chiral bridged metallocenes useful for the polymerization of isotactic polypropylene.
In addition, U.S. Pat. Nos. 6,846,770 and 6,664,348 further disclose metallocene catalyst compositions containing a support that has been fluorided using a fluoride-containing compound and their use in making polypropylene in a slurry process.
For those non-metallocene catalysts, such as pyridyl amines, have been used to prepare Group 4 complexes, which are useful transition metal components for use in the polymerization of olefins, see, for example, US 2002/0142912; U.S. Pat. Nos. 6,900,321; and 6,103,657; where the ligands have been used in complexes in which the ligands are coordinated in a bidentate fashion to the transition metal atom. Another example, U.S. Pat. No. 7,973,116 provides pyridyldiamido transition metal complexes and intermediates to polymerize olefins using such pyridyldiamido compounds. Other background references include US 2015/141590, US 2014/256893, US 2014/316089, WO 2013/028283, and WO 2014/123683.
It is desirable in the art to develop improved catalyst systems for the polymerization of olefins in order to achieve increased activity or specific polymer properties (such as high melting point and high molecular weight), to increase conversion or comonomer incorporation, or to alter comonomer distribution, without deteriorating the resulting polymer's properties.